In addition to the approved drug vismodegib, there are several more Hedgehog inhibitors (Hhi) in the drug development pipeline. Most of these compounds inhibit the hedgehog signaling pathway via antagonism of Smoothened (SMO), a key component of the pathway and include saridegib, erismodegib, BMS-833923 (XL139), TAK-441 and glasdegib (PF-04449913). SANT-3 and SANT-4 are SMO antagonists [3].